FutureStructure

Will Driverless Cars Solve or Worsen Traffic?

Researchers say the traffic- and pollution-reducing benefits of self-driving vehicles aren’t guaranteed — at least, not without serious societal changes in how people use cars.

by Melissa Santos, The News Tribune (Tacoma, Wash.) / June 28, 2017
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(TNS) -- A utopian image of the future involves shared fleets of electric-powered, driverless vehicles rapidly picking up and dropping off passengers, reducing traffic congestion and pollution in the process.

Gov. Jay Inslee seemed to embrace that vision this month when he signed an executive order promoting tests of self-driving cars on Washington roads.

Driverless cars “could help save countless lives, reclaim time spent in traffic, improve mobility and be an important tool in our efforts to combat climate change,” the Democratic governor said in a news release.

But researchers say the traffic- and pollution-reducing benefits of self-driving vehicles aren’t guaranteed — at least, not without serious societal changes in how people use cars.

Many researchers predict traffic congestion might worsen initially when more driverless cars come on the market, as people begin taking advantage of how convenient the technology is.

Pollution from car exhaust also could climb in the beginning, said Brandon Schoettle, a project manager with the University of Michigan Transportation Research Institute.

“The environmental aspect will probably get worse before it gets better,” said Schoettle, who has co-authored multiple papers on autonomous vehicles.

That’s largely because self-driving vehicles are expected to increase the amount of total miles driven, he said.

Not requiring a driver means that teenagers, people with disabilities and the elderly would suddenly be able to use cars when they couldn’t before, Schoettle said. That would most likely lead to more driving overall, he said.

Even if families ended up sharing one driverless car, the vehicle would rack up extra miles zipping back and forth between family members who need it, he said.

“You’re adding this extra usage to the vehicle because it’s convenient,” Schoettle said.

People also might end up using the self-driving vehicles more since the technology would let them do other tasks inside their car, like watch a movie or answer emails. That lowers the social cost of time spent in traffic, according to a report from the RAND Corporation, a nonprofit policy think tank.

The actual monetary cost of driving probably would go down, too, since self-driving vehicles — also known as AVs — are expected to drive more efficiently and burn less gasoline per mile.

“By reducing the marginal cost of driving, AV technology may actually lead to increased congestion in the short term,” wrote James Anderson, the lead author of the RAND study, in an email.

“I’m not aware of any research that seriously disputes this point, or the fact that there are just huge uncertainties.”

Still, Anderson wrote that self-driving cars “have considerable promise” in the long term.

The vehicles are expected to be much safer than human-driven cars, which should reduce collisions and help avoid some traffic backups caused by accidents, several studies predict.

And, if the self-driving cars all operate on electricity instead of gas, they could potentially slash pollution from automobiles over time, according to a recent report from the University of California Davis and the Institute for Transportation and Development Policy.

Traffic would improve, too, provided that people use driverless cars as a type of high-occupancy ride-sharing service instead of their own personal chauffeurs, according to the UC Davis report.

Yet the report acknowledges all of that would require a series of cultural and technological revolutions.

Not only would vehicles have to become automated and electric, but many people would have to change their habits and forgo use of personal vehicles, the report states.

The dramatic CO2 reductions envisioned with electric, self-driving vehicles would also require nearly the complete elimination of coal-fired power plants by 2050, according to UC Davis researchers.

Ultimately, reaping all the benefits of driverless cars “may require aggressive, visionary policy” from government agencies, the report concludes.

Emily McReynolds, program director for the Tech Policy Lab at the University of Washington, said that means embracing policies that encourage people to move away from individual ownership of autonomous vehicles, and toward a model that uses driverless cars more like public transit.

Failure to do that “may substantially reduce traffic efficiency by increasing the number of vehicles on the road,” according to a whitepaper that McReynolds co-wrote called “Driverless Seattle.”

“It’s all about the choices we make,” McReynolds said. “We can choose to encourage an individual model, which has the potential of increasing traffic congestion, or we can encourage a model that is more of a public-transit model, which can reduce traffic.”

According to McReynolds’ whitepaper, Seattle officials should consider planning for things like the new demand for curb-side parking that self-driving, ride-sharing vehicles could create. City officials might also look at how the automated cars could communicate with traffic signals to improve traffic flow.

Charles Knutson, a senior policy adviser to Inslee, said the governor’s office is focused on a future for self-driving cars that would include all of that.

The ideal would be a system of automated cars that is connected, electric and shared, Knutson said.

To that end, the governor is continuing to support incentives to jumpstart the use of electric vehicles, as well as to expand public transportation, biking and pedestrian improvements, Knutson said.

Inslee’s executive order this month also created a working group to keep an eye on emerging trends in automated vehicles.

Knutson said that group will be looking at ways to ensure traffic gets better with self-driving cars, rather than worse.

“I think the more we can focus our policies and funding on transit and electric vehicle incentives, the more we can avoid that scenario,” Knutson said. “We want to make this technology work for all of us.”

©2017 The News Tribune (Tacoma, Wash.) Distributed by Tribune Content Agency, LLC.